C172I avgas smell
 

Hi all....trying to track down a fuel smell. Can smell AVGAS at some very specific points in a flight. Firstly after taxiing for about 3-4 minutes (normally just as im running up)....within 30 seconds after takeoff and normally within about 2 minutes of landing (most prevalent during turbulence). Its not overwhelming, just a light wiff. At all other times there is no AVGAS smell.

Any common failure points on a C172 that people might know of? I've flown the plane for 200 hours without an increase or decrease in the problem.....im just sick of explaining its "always like that" to pax/people.

Re.172 Fuel smell
 

Obvious place to check first is the Fuel selector and associated fittings.

The fuel lines run down the door posts, so it may be worth removing the door trims to take a look.

Wing root rubber interconnect hoses have been know to perish - remove wing root fairings.

A few years ago i flew a 172 with a similar problem. During a lesson i was demonstrating the pitch up moment caused by lowering flap and was surprised to see that a further, more exciting effect was fuel coming out of the wing airvents and dripping onto the avionics.:sad:
To cut a long story short, after a very quick return to the field it was found that the new wingtank was not in the possition that it should have been.
As a result if you had full, or nearly full fuel, at certain points during the flight fuel would slop around and come out and all the fuel above a certain level would end up coming out of the tank onto you or the hot avionics! It would be a VERY good idea to get an engineer to check that the tank is in good condition and that it is sitting securley in the possition that it is intended.
Good luck and happy landings!

I find all small Cessna's smell AVGAS. Some more than other, I've never had a sick passenger during my flight, except one, and she got sick because of avgas smell, not because of turbulence.

I posted on a Canada thread where I am as well....seemed to get a lot of replies about fuel selector....sounds like first place to look....im guessing the plastic covering just unscrews....will check it out.

THanks
Stunty

Stunty,

Join the Cessna Pilots Association. The subject is well covered there on their forums.

The vent pipes that cross over the cabin have rubber hose connections and are the more normal cause especially with higher fuel loads.

Speedbird 48.